Questions tagged [vacuum]
The vacuum command in postgres releases unused space. Be sure to also include the [postgres] tag, and version tag such as [postgresql-9.6]. Include an operating system tag,
119
questions
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How to view the current settings of Autovacuum in Postgres?
I've found a million examples of how to set Autovacuum's configuration settings, but can't seem to find how to list the current configuration.
Postgres 9.1 is the version I'm most interested in.
43
votes
5answers
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Aggressive Autovacuum on PostgreSQL
I'm trying to get PostgreSQL to aggressively auto vacuum my database. I've currently configured auto vacuum as follows:
autovacuum_vacuum_cost_delay = 0 #Turn off cost based vacuum
...
38
votes
3answers
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Are regular VACUUM ANALYZE still recommended under 9.1?
I'm using PostgreSQL 9.1 on Ubuntu. Are scheduled VACUUM ANALYZE still recommended, or is autovacuum enough to take care of all needs?
If the answer is "it depends", then:
I have a largish database (...
35
votes
4answers
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I need to run VACUUM FULL with no available disk space
I have one table that is taking up close to 90% of hd space on our server. I have decided to drop a few columns to free up space. But I need to return the space to the OS. The problem, though, is ...
26
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1answer
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VACUUM returning disk space to operating system
VACUUM usually does not return disk space to operating system, except in some special cases.
From the docs:
The standard form of VACUUM removes dead row versions in tables and indexes and marks the ...
22
votes
4answers
36k views
How much time will a vacuum/autovacuum operation take?
I manage a big (some hundreds of gigs) database containing tables with various roles, some of them holding millions of records. Some tables only receive large number of inserts and deletes, some other ...
22
votes
3answers
25k views
VACUUM FREEZE vs. VACUUM FULL
Can someone explain the difference between these types of VACUUM in PostgreSQL?
I read the doc but it just says that FULL locks the tables and FREEZE "freezes" the tuples. I think that's the same. Am ...
19
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1answer
3k views
Is it worth it to run VACUUM on a table that only receives INSERTs?
In a 2015 re:Invent talk, AWS mentioned that vacuum should be run not only after updates or deletes but also after inserts. Here is the relevant part of the talk:
http://www.youtube.com/watch?v=...
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4answers
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Should I manually VACUUM my PostgreSQL database if autovacuum is turned on?
I use software which makes a big PostgreSQL database (there is a table with a million rows in it) and the developers says I should VACUUM and ANALYZE periodically. But the PostgreSQL database default ...
15
votes
2answers
12k views
PostgreSQL difference between VACUUM FULL and CLUSTER
I have a table with 200 GB of size occupied by data and 180 GB of size by the 6 indexes on it. It is 30% bloated, so I want to reclaim unwanted space occupied by it. It is clustered on job_id_idx ...
13
votes
1answer
16k views
Does cancelling an (AUTO)VACUUM process in PostgreSQL make all the work done useless?
In some occasions, and after making a massive update, insert or delete from a table, I have started a VACUUM FULL ANALYZE to make sure the DB was not getting too bloated. Doing it in a production ...
13
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1answer
661 views
Disk file effects of delete and vacuum
I have a very frequently updated table with 240 million rows (and growing). Every three hours 1.5 million rows are inserted and 1.5 million are deleted. When I moved the cluster to a SSD this bulk ...
11
votes
1answer
2k views
Busy table is not getting vacuumed
We're using Postgres 9.2 on Windows to store low-frequency timeseries data: we're inserting around 2000 rows per second every second 24 hours, 7 days a week with no downtime. There is a DELETE that ...
10
votes
2answers
2k views
What fillfactor for caching table?
I have heavily updated / accessed table where I store serialized java objects. They are in the table for 2-3 hours (also are being updated during that period) and then removed. Size of table is around ...
10
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1answer
4k views
Does VACUUM FULL need ANALYZE
I'd be grateful for some insight into the VACUUM functionality within PostgreSQL 9.3. I read through the documentation and searched around a bit but could not find a definitive answer to this.
I'm ...
9
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1answer
3k views
Reclaim disk space from dropped column without downtime
I have a heavily used table (with around 5 million rows) in a PostgreSQL database in which I want to drop a column and reclaim the space the column used.
The docs suggest doing a table rewriting ...
9
votes
1answer
7k views
PostgeSQL 9.3: Is it safe to stop VACUUM FULL?
I'm using PostgreSQL 9.3 on RDS. Once in a while, I run a VACUUM FULL operation on the database. However, such operation can take quite a while and it blocks other tables, so the need to stop the ...
9
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2answers
763 views
Does SELECT remove dead rows like VACUUM does?
I was fiddling with VACUUM and noticed some unexpected behavior where SELECTing rows from a table seems to reduce the work VACUUM has to do afterwards.
Test Data
Note: autovacuum is disabled
CREATE ...
9
votes
1answer
567 views
How to reclaim space taken by an index that partially built and was terminated by a power outage
I'm running postgres (postgis) 9.4.2 on a mac (10.10.4).
I've got a couple big tables (several TBs).
During an index build on one of them that takes about a week, I watched the available HD space ...
8
votes
4answers
7k views
VACUUM VERBOSE outputs, nonremovable “dead row versions cannot be removed yet”?
I have a Postgres 9.2 DB where a certain table has lots of nonremovable dead rows:
# SELECT * FROM public.pgstattuple('mytable');
table_len | tuple_count | tuple_len | tuple_percent | ...
8
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2answers
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Why wouldn't VACUUM ANALYZE clear all dead tuples?
We run a "manual" VACUUM ANALYZE VERBOSE on some of our larger tables after we do major DELETE/INSERT changes to them. This seems to work without issue although sometimes a table's VACUUM job will run ...
6
votes
1answer
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PostgreSQL strategies to deal with disk filling up
I'm using PostgreSQL (8.4) to store data produced by an application making frequent inserts (in the table structure described below).
The database keeps growing with time and, since the newer data is ...
5
votes
1answer
1k views
For alignment optimized table is bigger than original table - why?
In another question I learned that I should optimize the layout from one of my tables to save space and have better performance. I did this, but ended up with a larger table than before and ...
5
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1answer
135 views
How to predict how much space a VACUUM FULL would reclaim?
Is there a way to determine in advance how much disk space a VACUUM FULL on a particular table would return to the OS? Therefore you can decide whether it's worth the cost in doing so.
Bonus if there'...
5
votes
1answer
2k views
PostgreSQL maintenance
I am new to PostgreSQL and want to know more about maintenance options in pgAdmin III.
I've read the documentation and now I know that vacuuming frees some space and I need to run it regularly. ...
5
votes
1answer
393 views
How do databases deal with file system fragmentation?
Especially analytic databases that try to optimize for queries that scan large portions of tables instead of randomly accessing specific rows. For example Redshift has a concept of a sort key that, ...
4
votes
2answers
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PostgreSQL unexplained table bloat
I have a table in a Postgres 8.2.15 database. The table bloated to almost 25GB but after running vacuum full and cluster the table size was dramatically smaller, well under 1GB. A few weeks later ...
4
votes
1answer
2k views
Does postgres efficiently re-use space from deleted rows?
From the docs:
In PostgreSQL, an UPDATE or DELETE of a row does not immediately remove the old version of the row [...] But eventually, an outdated or deleted row version is no longer of interest ...
4
votes
3answers
3k views
How to reclaim disk space after delete without rebuilding table?
Our PostgreSQL 9.0 Windows production server is running low on space.
In our 100GB database, we have a large table containing TOASTed binary data. We have deleted some rows and need to return the ...
4
votes
1answer
935 views
Is it necessary to ANALYZE a table after an index has been created?
In my transaction, I am creating a temporary table:
create temporary table x on commit drop as
select ...
I also add an index on that table:
create index on x(some_column);
Is it now necessary to ...
4
votes
1answer
5k views
VACUUM FULL fails with 'ERROR: Check free disk space'
I am using Postgres 9.4. I have a database that \l+ tells me is 164 GB. When I try to run VACUUM FULL on the database, I get this error (after many hours):
ERROR: could not extend file "base/18222/...
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votes
1answer
3k views
Dropping indexes doesn't seem to release space to the OS. Can it?
I'm running PostgreSQL 9.1. I have noticed really alarmingly bad indexes are taking up a lot of space on my server, e.g:
evlampts=# SELECT
pg_size_pretty(pg_relation_size('mcdata_2011_07')) AS ...
3
votes
1answer
4k views
Postgres Vacuum in Function
After googleing a bit, it's plainly clear you cannot run vacuum from a function:
Postgres mailing - Vacuum behaviour in plpgsql function
You can't run VACUUM from inside a function because of ...
3
votes
1answer
679 views
Are autovacuum VACUUMs slower than a manual VACUUM?
I have a few large tables that take days to autovacuum, sometimes resulting in poor performance until the vacuum finishes. Most of the recommendations I've seen mention doing a manual VACUUM during ...
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votes
2answers
4k views
Vacuum vs Auto Vacuum
I am trying to find answers for my below few queries which will help me in fine tuning my postgres DB. I did some googling but was not able to find answer.
1) Out of vacuum or Auto vacuum which is ...
3
votes
1answer
4k views
Is VACUUM FULL necessary on a DROP TABLE / TRUNCATE approach for a datawarehouse
We are updating a datawarehouse on a weekly basis using a series of
TRUNCATE source_table1
COPY source_table1 FROM [...]
... for data import
and:
DROP TABLE IF EXISTS my_table
CREATE TABLE ...
3
votes
1answer
55 views
In PostgreSQL, if crashes during VACUUM, will it recover from a checkpoint that is before the frozen transaction ID of VACUUM?
When VACUUM starts, it will calculate a frozen transaction ID and freeze all tuples older than it. Will this frozen TXID be younger than the latest checkpoint?
If this is the case, then when the ...
3
votes
0answers
500 views
How do I fix multixact wraparound after it has already occurred?
I have a database which has a single table for which MultiXact wraparound has already occurred. Neither manual vacuums nor automatic vacuums are able to fix this condition.
Manual vacuums fail almost ...
3
votes
0answers
602 views
AWS Aurora Database Corruption
I'm running Aurora Postgres and noticed that metric Maximum Used Transaction IDs is increasing a lot. Trying to manually vacuum the tables that's was not automatically vacuumed lead me to the ...
3
votes
0answers
492 views
Stubborn autovacuum process slow things dows
We are facing a strange problem since yesterday.
In a database of ours there is a partitioned table containing historical data. That is, every week's data goes to a different partition and stays ...
2
votes
2answers
696 views
pg_relation_size does not show any difference after VACUUM ANALYZE
I wrote a script to backup a postgresql using COPY and then delete those records. I have used pg_relation_size before and after delete.
pg_relation_size
DELETE
VACUUM ANALYZE
pg_relation_size
But ...
2
votes
1answer
3k views
What are “nonremovable row versions”?
I did full vacuum on postgresql-9.4 database and I have a lot of tables with nonremovable row versions. I would like to know what are these or where I can read about them.
INFO: vacuuming "public....
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votes
1answer
2k views
“Truncate” or “Delete/Vacuum Full” for deleting some of the table rows
I have a db which has 223 tables and I have to delete some of the records from 10 of them, each has apprx. 1.5million records. Those tables are storing the temperatures every 7seconds. We have decided ...
2
votes
2answers
1k views
How to optimize a table for a very high-frequency updates?
I have a table that contains a list of tasks that need to be run periodically:
applaudience=> \d+ maintenance_task
Table "...
2
votes
3answers
2k views
Vacuum settings for mostly append-only data
I have a table with the following characteristics:
We INSERT a few 100k rows each day
We never UPDATE the rows
We DELETE "old" data once a week
From my shallow knowledge of Postgres VACUUM, it seems ...
2
votes
1answer
2k views
Time taken by VACUUM FULL to reclaim space
After receiving some insightful guidance in a previous post here, I'm going to run VACUUM FULL on 4 PostgreSQL 9.3.10 tables. Table sizes are:
1) links_publicreply: ~30M rows, 9 columns, 3 indexes (...
2
votes
1answer
2k views
Is it safe to kill vacuumdb?
I would like to schedule a vacuumdb cron job for an entire database, but I don't want it to run past a certain time. Is it safe to just stop the job with killall vacuumdb?
2
votes
1answer
46 views
How much disk space was made available to Postgres by VACUUM that is not available to the OS?
VACUUM does not return disk space to the OS, instead it marks dead rows to be reused for future writes. My server has almost ran out of disk space, afterwards I ran DELETE FROM big_table to clear ...
2
votes
1answer
211 views
Does AWS ever `vacuumlo` PostgreSQL RDS instances?
Link to the long story happened before (and reason to have) this question.
Does AWS ever vacuumlo PostgreSQL RDS instances?
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1answer
28 views
Does dumping/restoring do the same as “vacuum full”?
I have a large database running with PostgreSQL v11, and the disk space is very limited, so I have to VACUUM (FULL) the database frequently (e.g. every day).
But vacuuming is a very time-consuming ...
